1. Technical Field
The present invention relates to an input device which detects a position of an object as an input position.
2. Related Art
When a user carries out an input into an information processing apparatus, an input interface, such as a keyboard, a numeric keypad, or a mouse, is used. A pointing device for operating a pointer displayed on a display is known as one kind of input interface. Although the mouse is a typical pointing device, there is a drawback in that, from a standpoint of size and weight, it is not suitable for a portable information processing apparatus (for example, a portable telephone, a personal digital assistant (PDA), or a mobile personal computer (PC)). Meanwhile, a touch panel is attracting attention as a pointing device with greater portability. A user can carry out an operation to a device with a touch panel, such as a selection of a graphical user interface (an icon, a button, a menu, a checkbox, or the like), by bringing an object, such as a finger or a pen device (a stylus), into contact with a desired area on the display.
Also, a three-dimensional input device which detects the three-dimensional position of the object in relation to the display and utilizes the position as an input, is known. A computer navigation described in Japanese Patent Publication of Unexamined Applications (Kokai) No. 2005-529395 extrapolates the three-dimensional position of the object in relation to the display, based on an area and elliptic eccentricity of a conical infrared light radiated from a leading extremity of the object and falling incident on the display.
With a control device described in Japanese Patent Publication of Unexamined Applications (Kokai) No. 2007-531146, an electromagnetic radiation beam radiated from the leading extremity of the object onto the display is detected by multiple detectors provided on at least one edge of the display. Since the electromagnetic radiation beam attenuates before reaching the detectors from a collision position on the display, the control extrapolates the distance and angle to the display, which is the position, based on the strength of the radiation beam detected by the multiple detectors.